Pile anchor with external vanes

ABSTRACT

An elongated hollow member ( 160 ), as shown in FIG.  1 , with longitudinally disposed external vane(s) ( 275 A-B) for securing an offshore structure to the seafloor. The external vanes help maintain the heading and bearing of the anchor during the installation process, and may also enhance the pile anchor&#39;s holding capacity.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Stage of International Application No.PCT/US04/04742, filed 17 Feb., 2004, which claims the benefit of U.S.Provisional Application 60/451,734, filed 4 Mar., 2003.

FIELD OF THE INVENTION

This invention relates generally to pile anchor technology, and inparticular, to a novel pile anchor having external vanes. The externalvanes help maintain the heading and bearing of the anchor duringinstallation, and may also enhance the holding capacity of the anchor.

BACKGROUND OF THE INVENTION

Offshore structures, such as those used by the petroleum industry, aresometimes moored to the seafloor using pile anchors. Existing pileanchors may generally be described as a single tubular element,typically circular in cross section, with a closed top and an openbottom. The ability of a pile anchor to moor an object is typicallyreferred to as an anchor's “holding capacity.” In general, the holdingcapacity of a pile anchor increases with the size of the anchor.However, typically as the size of the anchor increases, so does theanchor's material, fabrication and installation costs. Additionalbackground can be found in U.S. Pat. No. 5,915,326 to Karal, GB U.S.Pat. No. 1,269,599 A to Joppa et al., U.S. Pat. No. 5,704,732 to Horton,and U.S. Pat. No. 4,619,218 to Kenny. What is needed is a pile anchorinstallation system that reduces the high costs of material, fabricationand installation without substantially reducing the anchor's holdingcapacity.

There is also a need in the industry for a pile anchor that can maintainits holding capacity at a reduced size, or alternatively, that has anincreased holding capacity for a given size. By increasing a pileanchor's holding capacity, one may be able to reduce the total number ofpile anchors required to moor a floating structure. Decreasing thenumber of pile anchors reduces the material costs and installation time,which can be a significant cost component of offshore construction. Thepresent invention may satisfy these needs.

SUMMARY OF THE INVENTION

This invention includes a pile anchor for use in mooring an offshorestructure to the seafloor. The anchor includes an elongated hollowmember having an upper end, an open lower end and a longitudinal axis, aload transfer device or means for connecting an anchor line to theelongated hollow member, a first longitudinally disposed vane extendingoutwardly from the outer surface of the elongated hollow member. Theelongated hollow member may be a circular tubular member. The upper endof the elongated hollow member alternatively has the capacity toregulate fluid flow. The load transfer device is fixed to the outersurface of the elongated hollow member. The elongated hollow memberalternatively has a second longitudinally disposed vane extendingoutwardly from the outer surface of the elongated hollow member.

The invention also includes a method of anchoring a pile anchor into thefloor of a body of water. The method includes installing a pile anchorinto the floor of the body of water. The pile anchor includes (i) anelongated hollow member having an upper end, an open lower end, alongitudinal axis and a transverse cross section, (ii) a load transferdevice for connecting an anchor line to the elongated hollow member, theload transfer device fixed to the outer surface of the elongated hollowmember and positioned on the circumference of the elongated hollowmember, and (iii) a first longitudinally disposed vane extendingoutwardly from the outer surface of the elongated hollow member.

Another embodiment of the invention provides a method of producingoffshore hydrocarbon resources. The method includes anchoring anoffshore structure to the seabed through use of a pile anchor. The pileanchor includes (i) an elongated hollow member having an upper end, anopen lower end, a longitudinal axis and a transverse cross section; (ii)a load transfer device for connecting an anchor line to the elongatedhollow member, the load transfer device fixed to the outer surface ofthe elongated hollow member and positioned on the circumference of theelongated hollow member; and (iii) a first longitudinally disposed vaneextending outwardly from the outer surface of the elongated hollowmember. The method further includes connecting the load transfer deviceto an offshore structure and producing hydrocarbon resources.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates one embodiment of a pile anchor according to theinvention.

FIG. 2 is a top view of one embodiment of an anchor in accordance withthis invention, which illustrates a padeye as the 0 degree referencepoint.

FIG. 3 is a schematic view of one embodiment of an anchor made inaccordance with this invention.

FIG. 4 is a schematic view of one embodiment of an anchor made inaccordance with this invention with an additional longitudinallydisposed vane attached to the back of the anchor FIG. 5 is a schematicview of one embodiment of this invention wherein slots are used tosecure the longitudinally disposed vanes to the tubular member.

FIG. 6 is a schematic view of one embodiment of the invention that hastwo-part planar vanes.

FIG. 7 is an overhead view of one embodiment of the invention that hastwo-part planar vanes.

FIG. 8 is a schematic view of one embodiment of the invention that hascurved non-planar vanes.

FIG. 9 is an overhead view of one embodiment of the invention that hascurved non-planar vanes.

FIG. 10 is a front-side schematic view of one embodiment of theinvention that has two-part planar vanes.

FIG. 11 is a back-side schematic view of one embodiment of the inventionthat has two-part planar vanes.

FIG. 12 is an overhead view of one embodiment of the invention that hastwo-part planar vanes.

FIG. 13 is a front-side schematic view of one embodiment of theinvention that has a single planar vane.

FIG. 14 is a back-side schematic view of one embodiment of the inventionthat has a single planar vane.

FIG. 15 is an overhead view of one embodiment of the invention that hasa single planar vane.

FIG. 16 illustrates an offshore spar that is anchored using the anchorsof the invention.

DETAILED DESCRIPTION OF THE INVENTION

As used herein and in the appended claims the phrase “elongated hollowmember” is meant to refer to any device that forms an enclosure on allits sides except that its top and bottom ends may be open or closed witha cap. For example, by way of illustration and not limitation, acircular, rectangular or elliptical conduit with a closed or open topand lower end. An elongated hollow member may be completely hollowwithin its interior or may be only partially hollow, for exampleincluding internal structural bracing within the elongated hollowmember. The elongated hollow members according to the invention may havean open lower end.

In general, pile anchors are installed by being lowered into the soil ina controlled descent, with the weight of the anchor being the initialdriving force. Cables are used to help control the descent of the pileanchor, and pressure release mechanisms, such as two-way flow valves onthe pile anchor, are opened to allow water to evacuate from interior ofthe pile anchor, thereby allowing penetration of the pile anchor intothe soil. This process is referred to as self-weight penetration.Usually self-weight penetration is followed by applying another force onthe anchor to obtain the final penetration depth. Typically, this forceis applied by way of suction penetration. In suction penetration, awater evacuation pump is attached to the suction pile anchor and wateris pumped out from the anchor's interior. The differential waterpressure that is created results in a net downward force that is used topush the suction pile anchor to final penetration. A direct force canalso be applied on the anchor, such as using a pile-driving hammer, toachieve final penetration. The direct force can be used either alone orin combination with suction penetration.

The anchoring device of this invention has the general configuration ofan elongated hollow member, but in addition has one or morelongitudinally disposed vanes located on the exterior of the anchor. Inone alternative embodiment the anchor has two vanes located on eitherside of the load transfer connection point. The vanes can be constructedof the same materials as the suction pile anchor, or other structuralmaterials as would be evident to one of ordinary skill in the art. Apile anchor may be any elongated hollow member, including a circularcylindrical member. It can be fabricated in other geometries, however,such as an elliptical cylinder, rectangular conduit, etc. and can havevarious length to diameter ratios.

An example of one embodiment of a pile anchor is provided in FIG. 1,which shows the pile anchor (100) as made up of a cylindrical body (160)that is closed at the top by a cap (150), and open at its lower end. Aload transfer connection point, such as a padeye (120), is located onthe side of pile anchor (100) to attach an anchor chain (130) whichtransfers the load from an offshore structure (not shown), such as afloating structure, DDCV, drilling or production riser, pipeline,semi-submersible, drilling vessel, subsea structure, or other structure.The anchor (100) includes at least one vane (275A) attached to the mainbody of the anchor and alternatively a second vane (275B). Cap (150)alternatively contains two-way flow valve(s) (110). Water evacuationpump (20) can be connected to a flow valve (110) to regulate fluid flowbetween the interior and exterior of the anchor to provide for suctioninstallation. During the installation process, the pile anchor (100) issupported by deployment hardware such as spreader bar (140), which inturn can be supported by a crane (or other surface machinery) throughcrane hook (30). Pile anchor (100) may be embedded in the sea floor (10)through the installation methods previously described and thosehereafter described.

Referring now to FIG. 2, for the purposes of describing this embodimentof the invention, the load transfer connection point, or padeye (120),will be considered as the 0 degree reference point. Measurement of thedeviation from this reference point is made in a clockwise direction.Referring again to FIG. 2, in accordance with one embodiment of thisinvention, at least one longitudinally disposed vane (275A) isalternatively located between about 45 degrees and about 135 degreesfrom padeye (120), and optionally a second longitudinally disposed vane(275B) is alternatively located between about 225 degrees and about 315degrees from padeye (120). However, the anchors according to theinvention may be constructed such that the vanes depicted in FIG. 2 areattached to the elongated hollow member (160) at angles greater or lessthan those specified in this paragraph, for example at about 35 to 145and about 215 to 325 degrees, at about 25 to 155 and about 205 to 335degrees or about 55 to 125 and about 235 to 305 degrees.

The length of the vanes (275A & 275B) that protrude from the elongatedhollow member can vary in both the longitudinal and radial directions.Generally these lengths can be optimized by designing vane lengths withreference to the soil conditions at the intended installation site usingengineering judgment. In this paragraph the referenced dimensions applyto the portion of the vane that is protruding from and exterior to theelongated hollow element. In one embodiment the vanes may be betweenabout 2 to 200 percent of the average diameter of the elongated hollowmember (160) in the radial direction. The vanes may alternatively bebetween about 5 to 90, 10 to 70, 15 to 60, or 20 to 55 percent of theaverage diameter of the elongated hollow member in the radial direction.The vanes may also be constructed to a certain length in thelongitudinal direction. In one embodiment the vanes are from 5 to 150percent of the average length of the elongated hollow member in thelongitudinal direction. The vanes may alternately be from 10 to 100, 25to 100, 50 to 100, 45 to 100, or 45 to 95 percent of the average lengthof the elongated hollow member in the longitudinal direction.

Referring now to FIG. 3, an embodiment of the current invention is shownwith vanes (275A) and (275B) located on the anchor (100) on either sideof padeye (120) in accordance with one embodiment of this invention.

Additional longitudinally disposed vanes can extend from the anchor(100). The additional vane or vanes can be located on the back and/orthe front of the anchor. The “front quarter” of the anchor includes theportion of the anchor extending from about 315 degrees to about the 0degree reference point and from about the 0 degree reference point toabout 45 degrees, or in other words from about 45 degrees on each sideof the padeye (120). The “back quarter” of the anchor is that section ofthe anchor that lies between about 135 degrees to about 225 degrees frompadeye (120). Referring to FIG. 4, a preferred embodiment of theinvention is shown containing an additional longitudinally disposed vane(275C) attached to the back quarter of the anchor.

Connection of the vanes to the anchor (100) can be accomplished bycommonly known methods. For example, the vane may be attached to theanchor's exterior by known welding techniques. In another preferredembodiment shown in FIG. 5, slots (215) are provided in anchor (100),and the vanes are attached to anchor (100) by inserting them through theslots (215) and then attaching the vanes to the slots using commontechniques, such as welding. When connecting the vanes to the anchor(100) through slots, a relatively tight seal is needed between the vaneand slot to prevent water from flowing into the anchor during suctioninstallation. Diametrically aligned vanes, for example vanes (275A) and(275B) shown in FIG. 4, may be fabricated in one piece and assembled tofit through both slots (215A) and (215B) in the suction pile anchor(100). In this configuration, the vanes in combination with otherassociated internal bracing (not shown) could also provide structuralsupport for the padeye (120).

The vanes (275A) and (275B) are depicted in this one embodiment asstraight planar elements coming off of the main body (160) of the anchor(100) perpendicular to a plane tangent to the anchor's main body (160)and parallel to the longitudinal axis of the main anchor body (160);however, the vanes according to the invention are not limited tostraight planar vanes, to vanes which are attached perpendicular to aplane tangent to the outer surface of the anchor's main body, nor tovanes parallel to the longitudinal axis of the main body of the anchor.The vanes according to the invention may be of many varied shapesincluding, but not limited to, curved vanes or vanes made up of multipleplanar elements attached at various angles in a hinged manner. Thevarious vane shapes may be attached in a substantially longitudinalmanner with respect to the main body of the anchor or be attached at anangle with respect to the longitudinal axis of the main anchor body. Thevanes may also be attached at an angle other than ninety degrees (i.e.perpendicular) from a plane that is tangent to the outer surface of themain body of the anchor.

FIG. 6 depicts an anchor (100) with two vanes (275A & 275B) that areattached to the elongated hollow member (160) at an angle relative to aplane tangent to the circular elongated hollow member (160). The vanes(275A & 275B) are also not a single planar shape, but are located in twoseparate planes that form an angle at the point of attachment. FIG. 7depicts an overhead view of the anchor (100) depicted in FIG. 6 whichfurther displays the angled attachment of the vanes (275A & 275B) andthe biplanar form of the vanes (275A & 275B).

FIG. 8 depicts an anchor (100) with two curved, semicircular, non-planarvanes (275A & 275B). FIG. 9 displays an overhead view of the anchor(100) and vanes (275A & 275B) depicted in FIG. 8.

FIG. 10 depicts an anchor (100) with two vanes (275A & 275B) that, whileattached perpendicular to the plane tangent to the circular elongatedhollow member (160), contain two planar vane elements which are attachedat an angle. The vanes are attached to the back side of the anchor (100)at about 135 degrees and 225 degrees respectively from the padeye (120).FIGS. 11 and 12 display the reverse angle and above view of the anchor(100) depicted in FIG. 10. However, the anchors according to theinvention may be constructed such that the vanes depicted in FIGS. 10,11, and 12 are attached to the elongated hollow member (160) at anglesgreater or less than those specified in this paragraph, for example atabout 125 and 235 degrees respectively from the padeye (120) or about145 and 215 degrees respectively from the padeye (120).

FIG. 13 depicts the front-side view of an anchor (100) that has a singleplanar vane (280) attached to the back-side of the anchor's main body(160) such that opposing ends of the vane act like separate vanes as inthe embodiment disclosed in FIGS. 1, 2 and 3. FIG. 14 presents thebackside view, while FIG. 15 presents an overhead view of the samesingle vane arrangement. The single vane of this configuration mayrequire additional external bracing (290) as depicted in FIG. 15.

In the various embodiments described herein, longitudinally disposedvanes (275A) and (275B) will also increase the soil bearing area of theanchor (100) against lateral displacement and will therefore increasethe anchor's holding capacity. Accordingly, with vanes (275A) and(275B), an anchor (100) may be designed smaller in size whilemaintaining a given holding capacity, thereby obtaining cost benefitsfor material and installation.

The dimensions, configuration and number of the vanes incorporated onanchor (100) can be determined by one of ordinary skill in the art basedupon factors including the application, the soil engineering properties,the bearing and heading of the anchor, the magnitude and types ofloading conditions, and the economies of fabrication and installationoperations.

The vanes aid in the installation of the anchor (100) by maintaining thebearing and heading of the anchor during self-weight penetration andsuction installation, or during installation by other methods. Thisability to maintain an anchor's bearing and heading is particularlyuseful for the installation method described in co-pending U.S. patentapplication Ser. No. 10/382,291, filed Mar. 5, 2003, titled Method forInstalling a Pile Anchor, the entirety of which is hereby incorporatedby reference herein. The referenced co-pending application discloses aninstallation method that enhances the holding capacity of a pile anchorby installing the pile anchor at an angle with respect to the seafloorso that the top of the anchor is inclined in a direction opposite to theapplied load. The anchor is positioned at an inclined angle with respectto the sea floor, with the top of the anchor inclined in a directionaway from the direction of lateral loading, and then inserted at leastpartially into the seafloor while the angle of inclination issubstantially maintained. The present invention therefore also includesa method for installing a pile anchor into the sea floor, and inparticular, the invention permits reducing or eliminating the verticalload acting upon a pile anchor and correspondingly increasing thelateral load component, thereby enhancing the anchor's holding capacity.An elongated hollow element, such as the pile anchor (100), embedded ina typical sea floor (10) stratigraphy can achieve a higher holdingcapacity when it is displaced through the soil perpendicular to itslongitudinal axis, as opposed to displacement along its longitudinalaxis. These load components represent lateral soil resistance (bearingresistance) and vertical soil resistance (sliding frictionalresistance), respectively. The preferred method for deploying thetubular member described herein will permit the pile anchor 100 to beinstalled so the vertical load component can be reduced incrementally,or completely eliminated.

As further described in co-pending U.S. patent application Ser. No.10/382,291, filed Mar. 5, 2003, titled Method for Installing a PileAnchor, a preferred embodiment of the invention where the anchor isinstalled at an angle the suction pile anchor 100 may be installed usinga guide frame to create and maintain the desired angle of inclination.In another preferred embodiment of the invention, the desired angle ofinclination is created and maintained by connecting a tensioning deviceto provide upward tension to the side of the pile anchor (100) on whichthe lateral load connection is applied, i.e., padeye (120). For example,anchor chain (130) may serve as the tensioning device for thisembodiment. Alternative tensioning devices can be used, which includebut are not limited to a lifting cable, or bar (or other rigid member).Another embodiment of this invention provides a pile anchor (100) withinternal compartments that can be selectively evacuated of water toprovide selective buoyancy for the pile anchor (100). By selectivelyadjusting the buoyancy of the pile anchor (100), the desired angle ofinclination can be achieved during installation. In another preferredembodiment the spreader bar (140) or other deployment hardware isattached to the pile anchor (100) at an offset position so that the axisof rotation is not through the center of gravity of the pile (100). Thespreader bar (140) or other deployment hardware is positioned such thatthe suction pile anchor (100) naturally assumes the desired angle ofinclination when it is deployed. Rigging cables or slings may beemployed in these embodiments to steady the suction pile anchor (100)during lowering and initial insertion into the sea floor (10).

The installation method disclosed above and in U.S. patent applicationSer. No. 10/382,291, filed Mar. 5, 2002, titled Method for Installing aPile Anchor, enhances the anchor's holding capacity. Accordingly,installation of the novel anchoring system (100) in conjunction with themethod disclosed in the referenced co-pending Patent Application mayprovide an anchor that can maintain the same holding capacity at areduced size.

FIG. 16 depicts an embodiment of the invention where pile anchors (100)are used to anchor an offshore structure (200) through use of anchorchains (130) connected to such pile anchors (100) through use of a loadtransfer device (120). The offshore structure (200) may be for example aspar (e.g. a deep draft caisson vessel (“DDCV”) or a truss spar) that isequipped with a deck (230). The deck (230) can support offshorehydrocarbon resource (i.e. oil and gas) exploration, drilling andproduction operations. The deck may be use to conduct offshore seismicdata collection. Alternatively, the deck can support offshore drillingequipment for oil and/or gas drilling operations. The deck may alsosupport oil and/or gas production equipment for the production of oiland gas natural resources. Produced oil and/or gas may then be offloadedfrom the deck by, for example, pipeline to shore or a transport ship orbarge and then moved to shore. The oil and gas may then be refined intousable petroleum products such as, for example, natural gas, liquefiedpetroleum gas, gasoline, jet fuel, diesel fuel, heating oil or otherpetroleum products.

The present invention has been described in connection with itspreferred embodiments. However, to the extent that the foregoingdescription is specific to a particular embodiment or a particular useof the invention, this is intended to be illustrative only and is not tobe construed as limiting the scope of the invention. On the contrary, itis intended to cover all alternatives, modifications, and equivalentsthat are included within the spirit and scope of the invention, asdefined by the appended claims.

1. A pile anchor, comprising: a. an elongated hollow member having anupper end, an open lower end and a longitudinal axis; b. a two-way flowvalve located on said elongated hollow member; c. a load transfer devicefor connecting an anchor line to said elongated hollow member, said loadtransfer device fixed to the outer surface of said elongated hollowmember and positioned on the circumference of said elongated hollowmember; and d. a first longitudinally disposed vane extending outwardlyfrom the outer surface of said elongated hollow member.
 2. The pileanchor of claim 1, further comprising a plurality of two-way flow valveslocated on said elongated hollow member.
 3. The pile anchor of claim 2,further comprising a second longitudinally disposed vane extendingoutwardly from said outer surface of said elongated hollow member. 4.The pile anchor of claim 3, wherein said first longitudinally disposedvane and said second longitudinally disposed vane have a longitudinallength that is about 50 to 100 percent of the average longitudinallength of the elongated hollow member.
 5. The pile anchor of claim 4,wherein said first longitudinally disposed vane and said secondlongitudinally disposed vane have a radial length that is about 5 to 90percent of the average diameter of the elongated hollow member.
 6. Thepile anchor of claim 5, wherein said elongated hollow member issubstantially tubular in shape and has a substantially circular crosssectional area.
 7. The pile anchor of claim 6, wherein said upper end ofsaid elongated hollow member is closed and wherein said valves arelocated on the upper end of said elongated hollow member, said valvesadapted for regulating fluid flow across said upper end of saidelongated hollow member.
 8. The pile anchor of claim 7, wherein saidload transfer device is positioned at the zero degree location on thecircumference of said elongated hollow member, said first longitudinallydisposed vane is positioned between about 25 degrees and about 155degrees from said zero degree location, and said second longitudinallydisposed vane is positioned between about 205 degrees and about 335degrees from said zero degree location.
 9. The pile anchor of claim 8,wherein said first longitudinally disposed vane is positioned betweenabout 45 degrees and about 135 degrees from said zero degree location,and said second longitudinally disposed vane is positioned between about225 degrees and about 315 degrees from said zero degree location. 10.The pile anchor of claim 9, further comprising at least one additionallongitudinally disposed vane extending outwardly from the outer surfaceof said elongated hollow member positioned between about 135 degrees andabout 225 degrees from said zero degree location.
 11. The pile anchor ofclaim 10, further comprising at least one additional longitudinallydisposed vane extending outwardly from the outer surface of saidelongated hollow member positioned between about 45 degrees on each sideof said zero degree location on the outer surface of said tubularmember.
 12. The pile anchor of claim 8, wherein said load transferdevice comprises a padeye.
 13. The pile anchor of claim 9, wherein saidfirst longitudinally disposed vane is attached through a first slot insaid elongated hollow member and said second longitudinally disposedvane is attached through a second slot in said elongated hollow member.14. The pile anchor of claim 13, wherein said first and second slots arediametrically opposed, and said first and second longitudinally disposedvanes comprise a single vane extending through said first and secondslots in said elongated hollow member.
 15. A method of anchoring a pileanchor into the floor of a body of water, comprising: installing a pileanchor into the floor of said body of water, said pile anchor including(i) an elongated hollow member having an upper end, an open lower end, alongitudinal axis and a transverse cross section, (ii) a two-way flowvalve located on said elongated hollow member, (iii) a load transferdevice for connecting an anchor line to said elongated hollow member,said load transfer device fixed to the outer surface of said elongatedhollow member and positioned on the circumference of said elongatedhollow member, and (iv) a first longitudinally disposed vane extendingoutwardly from the outer surface of said elongated hollow member. 16.The method of claim 15, wherein said elongated hollow member furthercomprises a plurality of two-way flow valves.
 17. The method of claim16, wherein said elongated hollow member further comprising a secondlongitudinally disposed vane extending outwardly from said outer surfaceof said elongated hollow member.
 18. The method of claim 17, whereinsaid first longitudinally disposed vane and said second longitudinallydisposed vane have a radial length that is about 5 to 90 percent of theaverage diameter of the elongated hollow member.
 19. The method of claim18, wherein said first longitudinally disposed vane and said secondlongitudinally disposed vane have a longitudinal length that is about 50to 100 percent of the average longitudinal length of the elongatedhollow member.
 20. The method of claim 19, wherein said load transferdevice is positioned at the zero degree location on the circumference ofsaid elongated hollow member, said first longitudinally disposed vane ispositioned between about 45 degrees and about 135 degrees from said zerodegree location, and said second longitudinally disposed vane ispositioned between about 225 degrees and about 315 degrees from saidzero degree location.
 21. The method of claim 19, wherein said elongatedhollow member is substantially tubular in shape and has a substantiallycircular cross sectional area.
 22. The method of claim 21, wherein saidupper end of said elongated hollow member is closed and wherein saidvalves are located on the upper end of said elongated hollow member,said valves adapted for regulating fluid flow across said upper end ofsaid elongated hollow member.
 23. The method of claim 22, wherein saidelongated hollow member further comprises at least one additionallongitudinally disposed vane extending outwardly from the outer surfaceof said elongated hollow member positioned between about 135 degrees andabout 225 degrees from said zero degree location.
 24. The method ofclaim 23, wherein said elongated hollow member further comprises atleast one additional longitudinally disposed vane extending outwardlyfrom the outer surface of said elongated hollow member positionedbetween about 45 degrees on each side of said zero degree location onthe outer surface of said tubular member.
 25. The method of claim 24,wherein said load transfer device comprises a padeye.
 26. The method ofclaim 20, wherein said first longitudinally disposed vane is attachedthrough a first slot in said elongated hollow member and said secondlongitudinally disposed vane is attached through a second slot in saidelongated hollow member.
 27. The method of claim 26, wherein said firstand second slots are diametrically opposed, and said first and secondlongitudinally disposed vanes comprise a single vane extending throughsaid first and second slots in said elongated hollow member.
 28. Themethod of claim 20, wherein said installation step includes: a.positioning said pile anchor at an inclined angle with respect to thesea floor, the top of said pile anchor being inclined in a directionaway from the direction of a lateral loading; and b. inserting said pileanchor at least partially into said sea floor, said pile anchorsubstantially maintaining said inclined angle.
 29. A method of producingoffshore hydrocarbon resources, comprising: a. anchoring an offshorestructure to the seabed through use of a pile anchor system, said pileanchor system including (i) an elongated hollow member having an upperend, an open lower end, a longitudinal axis and a transverse crosssection, (ii) a two-way flow valve located on said elongated hollowmember, (iii) a load transfer device for connecting an anchor line tosaid elongated hollow member, said load transfer device fixed to theouter surface of said elongated hollow member and positioned on thecircumference of said elongated hollow member, and (iv) a firstlongitudinally disposed vane extending outwardly from the outer surfaceof said elongated hollow member; b. connecting said load transfer deviceto an offshore structure; and c. producing hydrocarbon resources. 30.The method of claim 29, further comprising transporting said hydrocarbonresources to shore.